Its very simple, and there is something real cool about Dart that we see here:

toStringAsPrecision(3)

This automatically rounds the number up or down. So the number -1.117214930923896 gets -1.12. I think this really makes many things easier when you work with this kind of math things. Another nice thing that you can see here is the following print-method:

print("beta = $beta°");

No need to use tokens like ‘+’ or ‘.’. Just use ‘$’. By the way, the output looked like that: